Polyester meat shroud

ABSTRACT

Nonswelling nonwicking meat shrouds of high tenacity polyethylene terephthalate staple fibers with inherently low moisture regain provide superior conductivity while conditioning meat carcasses in the chilling stages without excessive dehydration.

United States Patent 1 1 3,741,260 Kocay 1 June 26, 1973 [5 POLYESTER MEAT SHROUD 3,104,450 9/1963 Christens et al. 57/140 R 1969 A l' I [75] Inventor: Witold R. Kocay, Creve Coeur, Mo. 2x isa u 73 Assigneez Monsanto Company, St. Louis 3,544,404 12/1970 Johnson et al 139/389 [22] Filed: June 1971 Primary Examiner l lenry S. Jaudon [21] Appl. No.: 156,061 Attorney-Elmer .l. Fischer, Thomas Y. Awalt, Jr.

et al.

[52] U.S. Cl 139/420 R, 57/140, 99/174 0 [51] Int. Cl D03d 15/00 ABSTRACT [58] Field of Search 139/383, 384, 387, Nonsweuin g nonwic mg meat shrouds of high tenacity 139/389 57/140 99/174 polyethylene terephthalate staple fibers with inherently low moisture regain provide superior conductivity [56] References cued while conditioning meat carcasses in the chilling stages UNITED STATES PATENTS without excessive dehydration. 3,275,455 9/1966 Williams 57/140 R 5 Claims, No Drawings POLYESTER MEAT SHROUD This invention relates to the conditioning of animal carcasses after slaughtering and skinning during which the carcasses are shrouded and placed in a cool atmosphere. At this time the surface fat is smoothed and bleached, and the carcass temperature is lowered to about the freezing temperature. Meat shrouds have been produced from cotton, ramie and rayon. Generally speaking, moisture regain, wicking, water swelling, water retention, and high wet-modulus were considered essential characteristics to be sought in meat shrouds in order to prevent the dehydration of the meat in order to absorb blood so that the surface of the meat is as blood-free as possible.

In addition to the aforementioned characteristics sought, it was also considered essential that meat shrouds have high strength and resistance to tear and a soil and stain release as well as stability to withstand chlorine bleaching without serious fiber damage for the reason that mean shrouds are laundered after each use and must be reasonably clean for reuse.

it is an object of this invention to provide a meat shroud which will function to prevent excessive dehydration of the meat carcass, all the while providing sufficient absorption of blood along with high breaking strength.

It is yet another object of this invention to provide a method for the preparation of meat shrouds from polyester fibers which are the functional equivalents of other meat shrouds, but having the low moisture regain and absorption characteristic with consequent ease of soil and stain release in conjunction with high breaking strength normally expected in polyester fibers and fabrics. These and other objects of the invention will become apparent from a consideration of the following specification and claims.

In accordance with this invention, meat shrouds are produced, a substantial portion of which comprises a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 85 percent by weight of an ester of a dihydric alcohol and terephthalic acid, the fibers being characterized by a denier of from about 4 to 8; a tenacity of at least about grams per denier, a very low moisture regain; spun yarn being characterized by a staple length of at least about 3 inches, an elongation of about percent, and a shrinkage of about 5.5 percent; the fabric being characterized by a percentage of absorbency of about 85-140, a skewer strength of at least about 80 pounds, a grab strength of at least about 140 pounds in both warp and fill direction, a residual boiling water shrinkage of about 2 percent, and high abrasion resistance.

I have discovered that polyester meat shroud cloths made in accordance with these specifications can be as effective as presently used 100 percent ramie, cotton, or other cellulosic cloth, in preventing the dehydration of whole beef carcasses.

The terms used above are employed in the usual meaning in the textile art except as follows: Skewer strength is a laboratory test designed to measure the pounds of force required to rupture the fabric when strained by a skewer of similar design to that actually used in a packing plant during the shrouding operation. After wetting, a specimen from the fabric is punctured by the skewer near one end and the opposite end is clamped in the stressing jaw of a tensile tester at a constant rate of extension. The cross-wise yarns are pulled against the skewer until a number have ruptured. The force is recorded automatically on a chart calibrated in units of pounds. The average of the individual yarn breaks for each principle direction is reported for the sample. The value obtained is a function of the individual yarn strength plus the support of the adjacent yarns. Calculation of the average force is based on ASTM Standard D-226l Tearing Strength of Fabrics by Tongue Method (Constant Rate-of-Extension Tensile Testing Machine) The average of the five highest peaks recorded on the chart is reported. Specimens having filling yarns parallel to the long dimension are used for testing the warp yarns, and specimens with the warp yarns parallel to the long dimension are used for the test of the filling yarns. All specimens are soaked in distilled water for 2 hours, removed and blotted lightly to remove surface water. The skewer position is deter mined by means of a 3 inch square template drilled with a inch hole in the center. Using the template, the skewer is positioned 1% inches from the end of the sample. Before inserting the skewer, a pencil or similar instrument is used to spread the yarns in the form of a hole. The skewer projection is fastened to the upper grip of the tensile tester and the other end of the sample is clamped in the lower grip. The tensile tester is operated with cross-head speed (rate of extension) of 5 inches/minute, a chart speed (recorder) of 10 inches/minute, a load scale of 200 pounds, a jaw separation (between clamps) of 6 inches, and with jaw faces (smooth) at l by 3 inches.

Abrasion Resistance has been measured according to tests conducted with a Wyzenbeek Abrader, a machine performing a unidirectional abrasion using a fixed tension, fixed head load, and preselected abrasive. The tension and head load were set at 2 pounds and the abrasive was No. 600A Soft Back supplied by Minnesota Mining and Manufacturing Company. The samples were abraded to 100, 200, 300 and 400 rubs after which each sample was weighed and then raveled to a 1 inch strip and broken. The weighed samples were compared against the original weight to determined fiber loss and the strength was compared against that of the original sample to determined strength loss. Tests were conducted on selvage and regular fabric specimens.

A so-called.flat abrasion test was also conducted on the Stoll Universal Wear Tester. This is a unidirectional abrasion of fabric to abrasive, the same abrasive being used as in the Wyzenbeek test, a head load of 1 pound was selected in a conjunction with abrasions of 1,000, 2,000, 3,000, and 4,000 cycles. As in the Wyzenbeek test, samples were weighed and broken before and after each abrasion.

Moisture absorbency" as referred to herein is according to a test run on meat shroud samples cut into squares to 22 centimeters. The sample is weighed after conditioning at standard conditions; then soaked in distilled water for 15 minutes. One corner of the sample is then removed from the water using tweezers, and allowed to drip for 30 seconds after which the sample is weighed. It is then hung under standard conditions from two corners for 3 hours, and weighed again.

The grab strength test or grab test is a standard method of test for textile fabrics and is known as ASTM heating one or more of the glycols of the series HO(CH2)HOH, in which his an integer of froin2 to 10 with one or more dicarboxylic acids or ester-forming derivatives thereof. Among the dicarboxylic acids and ester-forming derivatives thereof useful in the present invention there may be named terephthalic acid, isophthalic acid, p,p-dicarboxy-biphenyl, p,p'-dicarboxydiphenyl sufone, p,p'-dicarboxy-diphenyl methane, and the aliphatic, cycloaliphatic, and aryl esters and half esters, ammonium and amine salts, and the acide halides of the above compounds, and the like. Examples of polyhydric alcohols which may be employed in the manufacture of these fibers are ethylene glycol, trimethylene glycol, cyclohexane dimethanol, and the like. Polyethylene terephthalate is the preferred polymer because of the ready availability of terephthalic acid or dimethyl terephthalate and ethylene glycol, from which it is made. It also has a relatively high melting point of 250-265C., and the fibers are, in themselves more readily wettable as compared, for example, with nylon or polypropylene.

l have discovered that meat shrouds prepared from these polyester fibers can be as effective as 100 percent ramie cloth in the prevention of dehydration of whole beef carcasses, with other properties being superior to ramie shroud cloths or other cellulosic fiber shroud cloths.

EXAMPLES Polyethylene terephthalate fibers of 5.2 denier, a tenacity of 8 grams per denier, and having an elongation of 20 percent were cut into 6 inch staple. Yarn prepared from this staple fiber as both singles and plied had the following specifications:

TABLE I Yarn Physicals Singles Plied Yarn Number, w.c. 1/21.1 2/2114 Breaking Strength, lbs. 4.15 9.26 SE? 1400 1511 Elongation, I: 14.7 16.5 Shrinkage, 5.0 5.7 Skein Break, 120 yds.. lbs. 414 Break Factor 8750 Fabric prepared from the 2 ply yarn was according to the following specification:

TABLE II Warp: Width 46 inches Ends 1128 lncl. selvage Draw Straight 4 Harness Weave Plain Loom X-S Cam Reed 12/2/1 ground 12/311 selvage Pick Gear 25 Fabric constructed from the doubled yarn had a grab strength averaging about 275 pounds in both warp and fill direction and a skewer strength of 127.0-140.0 pounds. Residual boiling water shrinkage was about 2 percent.

A fabric constructed from the singles yarn and with 21 ends and 26 picks, fabric weight of about 6.0 ounces per square yard in a final width of about 39.5 inches, had a skewer strength of 104-143 pounds and a residual fabric shrinkage at the boil of about 1 percent. Shroud cloths of polyester and ramie were compared to determine their relative ability to prevent dehydration of whole beef carcasses. Polyurethane sponges and carborundum stones were saturated with 100 F. water (corresponding to the body temperature of beef cattle) and then wrapped in commercially available ramie and polyester shroud cloths (prepared as above with the 2 ply yarn) that had been previously wetted-out in an F. brine solution. The dry weights and amount of water absorbed by sponges and stones are shown in Table 111. The shrouded sponges and carborundum stones were suspended from a rod and placed in a refrigerator at a controlled temperature of 41-43 F. After 24, 48, and 72 hours in the refrigerator they were each removed and individually weighed. The results are shown at Table IV. During the testing it was noticed that the external surfaces of the ramie fabric remained moist whereas the polyester shroud surface felt dry. This difference was probably due to the fact that the ramie natural fiber had a higher moisture regain than synthetic polyester fiber.

TABLE lll Dry Weights of and the Amount of Water Absorbed by the Shrouded Sponges and Carborundum Stones g. Weight used as the denominator in the calculations of Table IV percent moisture loss values.

TABLE IV Percent Moisture Loss by Saturated Sponges and Carborundum Stones Wrapped in Ramie and Polyester Shroud Fabricafter 24, 48, and 72 hours in a 41-43 F. Refrigerator Ramie 100% Polyester Sponge Stone Sponge Stone After 24 Hours 18.8% 23.6% 15.8% 19.5%

After 48 Hours 29.1% 44.7% 26.7% 37.6% After 72 Hours 36.9% 63.1% 35.2%

Since the sponges and stones wrapped in ramie had a higher percent moisture loss than those wrapped in polyester, it might appear that the polyester shroud cloths would better prevent dehydration than the ramie cloths, but that the polyester shroud cloths would be relatively ineffective in removing blood from the carcass. Field trails have shown that although the polyester fiber itself can and does absorb a substantial amount of the blood, the fabric construction and the staple yarn itself provides additional interfilament absorption of the blood, the combined effect being more than satisfactory for commercial use.

Wyzenbeek and Stoll abrasion tests were run on samples of commercially available ramie shrouds and on polyester shrouds, the latter having been constructed as indicated above with the two ply yarn. These test were conducted on selvage and regular fabric specimens.

The results of both Wyzenbeek and Stoll Abrasion testing is shown at Table V.

TABLE V Wyzenbeek Abrasion Ramie Polyester Polyester Sel- Body Sel-Body Sel- Body vage vage vagc Breaking Strength, lbs. (1" Width, Warp) Original 248 147 306 224 301 223 After 100 Cycles 256 153 283 206 313 216 After 200 Cycles 222 68 264 158 291 164 After 300 Cycles 49 256 124 306 172 After 400 Cycles 26 250 130 266 104 Weight Loss, mgs After 100 Cycles 29.6 2L2 35.6 22.0 After 200 Cycles 66.2 103-1 33.1 43.0 After 300 Cycles 160-1 40.6 56.9 After 400 Cycles 177-3 -1 50.4 79.8

Stoll Flat Abrasion Break Strength, lbs. (1" Width, Warp) Original 248 147 306 224 301 223 After 1000 Cycles 126 310 176 307 176 After 2000 Cycles 282 101 259 I84 312 156 After 3000 Cycles 84 285 161 310 165 After 4000 Cycles 170 85 218 136 302 170 Weight Loss, mgs After 1000 Cycles 19.4 6.0 3.4 5.0 7.3 After 2000 Cycles 8.7 30.5 3.9 0.1 13.0 6.4 After 3000 Cycles 47.1 1.4 4.9 12.8 3.0 After 4000 Cycles 20.6 53.0 9.6 6.9 12.1 18.0 Wyzenbeek Abrasion Strength Retained, p) After 100 Cycles 100 100 92.5 92 100 97 After 200 Cycles 89.5 46 86.5 70.5 97 74.5 After 300 Cycles 27 83.5 55.5 100 77 After 400 Cycles 17.5 81.5 58 88.5 46.5

Stoll "Flat" Abrasion Strength Retained, (Warp) After 1000 Cycles 86 100 78.5 100 79 After 2000 Cycles 100 68.5 85 82 100 70 After 3000 Cycles 57 93 72 100 74 After 4000 Cycles 68.5 57.5 71 61 100 76 We claim:

1. Meat shrouds comprising fabric, a substantial portion of which comprises spun yarn, a substantial portion of which comprises a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 85 percent by weight of an ester of a dihydric alcohol and terephthalic acid,

said fibers being characterized by:

a. a denier of from about 4 to 8;

b. a tenacity of at least about 5 gpd;

c. a moisture regain of about 0.4; said spun yarn characterized by:

a. a staple length of at least about 3 inches;

b. an elongation of about 15 percent;

c. a shrinkage of about 5.5 percent; said fabric being characterized by:

a. a percentage of absorbency of about -140;

b. a skewer strength of at least about 70 pounds;

0. a grab strength of at least about pounds in both warp and fill direction; I

d. a residual boiling water shrinkage of about 2 percent;

e. a Wyzenbeek abrasion strength retention (warp) after 300 cycles of at least about 50 percent.

2. The meat shroud of claim 1 wherein the skewer strength is at least about 85 pounds.

3. The meat shroud of claim 1 wherein the grab strength is at least about pounds in both warp and fill direction.

4. The meat shroud of claim 1 wherein the staple length is about 4 inches.

5. Meat shrouds comprising fabric, a substantial portion of which comprises spun yarn, a substantial portion of which comprises a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 85 percent by weight of an ester of a dihydric alcohol and terephthalic acid, said fibers being characterized by:

a. a denier of from about 5 to 8;

b. a tenacity of at least about6 gpd;

c. a moisture regain of about 0.4; said spun yarn characterized by:

a. a staple length of at least about 4 inches;

b. an elongation of about 15 percent;

0. a shrinkage of about 5.5 percent; said fabric being characterized by;

a. a percentage of absorbency of about 97-140;

b. a skewer strength of at least about 85 pounds;

c. a grab strength of at least about 150 pounds in both warp and fill direction;

d. a residual boiling water shrinkage of about 2 percent;

e. a Wyzenbeek abrasion strength retention (warp) after 300 cycles of at least about 50 percent. 

2. The meat shroud of claim 1 wherein the skewer strength is at least about 85 pounds.
 3. The meat shroud of claim 1 wherein the grab strength is at least about 150 pounds in both warp and fill direction.
 4. The meat shroud of claim 1 wherein the staple length is about 4 inches.
 5. Meat shrouds comprising fabric, a substantial portion of which comprises spun yarn, a substantial portion of which comprises a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 85 percent by weight of an ester of a dihydriC alcohol and terephthalic acid, said fibers being characterized by: a. a denier of from about 5 to 8; b. a tenacity of at least about 6 gpd; c. a moisture regain of about 0.4; said spun yarn characterized by: a. a staple length of at least about 4 inches; b. an elongation of about 15 percent; c. a shrinkage of about 5.5 percent; said fabric being characterized by; a. a percentage of absorbency of about 97-140; b. a skewer strength of at least about 85 pounds; c. a grab strength of at least about 150 pounds in both warp and fill direction; d. a residual boiling water shrinkage of about 2 percent; e. a Wyzenbeek abrasion strength retention (warp) after 300 cycles of at least about 50 percent. 